Galena Complex Silver-Lead Recovery via Flotation and Milling

Source: Americas Gold and Silver Corporation (2026)
Website: https://americas-gold.com/operations/galena-complex/

Critical Data

Overview

The Galena Complex, operated by Americas Gold and Silver Corporation in Shoshone County, Idaho, is a historic silver-lead-copper operation that has been in production since 1922. Originally built with a 100 ton per day capacity, the Galena mill has undergone multiple expansions and upgrades, reaching a current capacity of 700 short tons per day (stpd) and a planned modernization to 1,200 tpd. The facility processes a blend of silver-copper and silver-lead ores, primarily from underground mining, to produce a lead concentrate shipped to Teck Metals Limited’s Trail Smelter in British Columbia, Canada. The recovery flowsheet combines crushing, grinding, flotation, and dewatering to achieve exceptional metal recoveries: 98% for silver and copper, and 93% for lead. In 2025, the mill treated 97,173 tons of ore with head grades of 490 g/t silver, 0.26% copper, and 3.7% lead, yielding over 1.45 million ounces of silver. The processing method leverages rougher-scavenger-cleaner flotation circuits, with tailings partly used for underground backfill (55%) and the remainder stored in a permitted impoundment facility with 25 years of capacity. This integrated approach maximizes recovery while supporting sustainable mining practices.

Key Process Stages

• Stage 1: Primary and Secondary Crushing Ore from the mine is dumped into a 400-ton coarse ore bin and fed by a Pioneer pan feeder to a 2 ft × 3 ft Kue Ken jaw crusher. Secondary crushing uses a 3 ft standard cone crusher in closed circuit with a 4 ft × 12 ft vibrating single-deck horizontal screen. The final product, minus 5/8 inch, is conveyed to a 300-ton fine ore bin.
• Stage 2: Grinding and Classification Ore passes over a weightometer for feed rate measurement and daily moisture grab sampling. It is fed to a 9 ft × 12 ft ball mill. Discharge passes over a 3 ft × 6 ft vibrating screen before entering cyclone classification. Cyclone underflow returns to the ball mill, while overflow reports to rougher flotation.
• Stage 3: Rougher Flotation Cyclone overflow enters a bank of four 100 ft³ Denver flotation cells for rougher flotation. Here, a bulk lead-silver-copper concentrate is collected, while rougher tails advance to the scavenger circuit.
• Stage 4: Scavenger Flotation Rougher tails feed four additional 100 ft³ Denver flotation cells for scavenging. Scavenger tails either go to the tailings facility or are used for underground backfill. The scavenger concentrate is recirculated to the rougher bank to maximize recovery.
• Stage 5: Cleaning and Concentrate Dewatering Rougher concentrate undergoes two stages of cleaning in Denver Sub-A flotation cells. The final cleaner concentrate is sampled and pumped to a 10 ft high × 20 ft diameter thickener. Thickened concentrate is filtered on parallel drum filters, and the filter cake is loaded onto trucks for shipment to the smelter.

Additional Interesting Data and Summary

The Galena Complex’s recovery methods are supported by a second idle facility—the Coeur mill, located five miles away with a 500 tonnes/day capacity, currently on care and maintenance—and a comprehensive tailings management system. Approximately 55% of mill tailings are returned underground as backfill, reducing surface disposal volumes and enhancing mine stability. The remaining tailings are sent to a storage facility near Osburn, Idaho, where the dam is raised annually in 1-meter lifts. The current permit allows at least 25 years of storage at 2025 production rates. Environmentally, the backfill practice minimizes surface footprint and water usage, while the tailings impoundment is constructed and monitored in compliance with regulatory permits. Economically, the Galena Complex directly supports regional employment and contributes to the local supply chain through trucking and smelter contracts with Teck Metals. The planned modernization program to increase mill throughput to 1,200 tpd will leverage existing flotation infrastructure, potentially improving economies of scale and reducing unit operating costs. Future outlook includes sustained ore supply from ongoing mine development, with head grades expected to remain near 2025 levels. The 98% silver and copper recoveries benchmark the plant’s efficiency, while lead recovery at 93% offers room for optimization through reagent or circuit modifications. Sustainability initiatives, such as tailings backfill and dam-raising practices, align with industry best practices for long-term asset stewardship. The combination of high recoveries, a permitted storage facility with decades of capacity, and a clear expansion pathway positions the Galena Complex as a key silver-lead producer in the Coeur d’Alene mining district.

Key Processes: Flotation, Ball Mill, Crushing

Target Commodities: Gold, Silver, Copper, Lead